Medical device for modification of left atrial appendage and related systems and methods

ABSTRACT

A medical device, system and method for modifying a left atrial appendage (“LAA”). The medical device system includes a tether anchored within the LAA and one or more tissue growth members or occluders configured to be slid over the tether and lodged within the LAA. With this arrangement, a physician may close-off the LAA with a selective number of tissue growth members to meet the varying LAA sizes as determined from imaging information while conducting the procedure.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 12/684,764, filed on Jan. 8, 2010, which claims the benefit ofU.S. Provisional Patent Application No. 61/143,360, filed Jan. 8, 2009,entitled MEDICAL DEVICE FOR MODIFICATION OF LEFT ATRIAL APPENDAGE ANDRELATED SYSTEMS AND METHODS, and of U.S. Provisional Patent ApplicationNo. 61/160,247, filed Mar. 13, 2009, entitled MEDICAL DEVICE FORMODIFICATION OF LEFT ATRIAL APPENDAGE AND RELATED SYSTEMS AND METHODS,and of U.S. Provisional Patent Application No. 61/164,313, filed Mar.27, 2009, entitled MEDICAL DEVICE FOR MODIFICATION OF LEFT ATRIALAPPENDAGE AND RELATED SYSTEMS AND METHODS, the disclosure of each ofwhich are incorporated by reference herein in their entireties.

TECHNICAL FIELD

The present invention relates generally to the modification of an atrialappendage and, more specifically, to devices, systems and methods foroccluding or otherwise structurally altering such appendages.

BACKGROUND

The atrial appendage is a feature of all human hearts. The upperchambers of the heart, the atria, have this appendage attached to eachof them. The physiologic function of such appendages is not completelyunderstood, but they do act as a filling reservoir during the normalpumping of the heart. The appendages typically protrude from the atriaand cover an external portion of the atria. Atrial appendages differsubstantially from one to another in size, shape and specific locationwith respect to the atria. For example, one atrial appendage may beconfigured as a tapered protrusion while another atrial appendage may beconfigured as a re-entrant, sock-like hole. The inner surface of anappendage is conventionally trabeculated with cords of muscular cardiactissue traversing its surface with one or more lobes.

The atrial appendages are inert while blood is being pumped through themduring normal heart function. In other words, the appendages don't havea noticeable effect on blood pumped through them during normal heartfunction. However, in cases of atrial fibrillation, when the atria gointo arrhythmia, blood may pool and thrombose inside of the appendages.Among other things, this can pose a stroke risk when it occurs in theleft appendage since the thrombus may be pumped out of the heart andinto the cranial circulation. Such can also lead to ischemic damage ofother organs of the body.

Historically, atrial appendages have sometimes been modified surgicallyto reduce the risk imposed by atrial fibrillation. In more recent years,devices which may be delivered percutaneously into the left atrialappendage have been introduced. The basic function of these devices isto exclude the volume within the appendage with an implant which thenallows blood within the appendage to safely thrombose and then to begradually incorporated into cardiac tissue. This can leave a smooth,endothelialized surface where the appendage used to be.

In comparison to surgical procedures, devices implanted percutaneouslyare clearly a less invasive means for addressing the problems associatedwith the left atrial appendage. However, due to the wide variability ofthe size of the ostium and the volume of an atrial appendage, implantdevices that are currently used typically include structure that cannotmeet such variability, resulting in inadequate devices for many leftatrial appendages. Further, such implant devices are substantiallylimited by the orientation by which they can successfully be deployed.Thus, successful placement and deployment of such devices becomeslimited.

As such, it would be advantageous to provide percutaneous systems,methods and devices that, among other things, address one or more issuessuch as implant orientation and the variability in sizes of the leftatrial appendage in order to provide high success in left atrialappendage modification.

BRIEF SUMMARY

The present invention includes various embodiments of medical devices,systems and methods for modifying an atrial appendage. In accordancewith one embodiment, a medical device system for modifying a left atrialappendage is provided. The system includes a catheter having a lumenextending therethrough. A tether extends through the lumen of thecatheter and an anchoring member is coupled with the tether. At leastone tissue growth member is slidably coupled with the tether and sizedand configured to be positioned within the left atrial appendage. Alocking element is associated with the at least one tissue growth memberand the tether.

In one embodiment, the tissue growth member may include a foam material.In certain embodiments the at least one tissue growth member may includea plurality of tissue growth members which are similarly or differentlyconfigured as compared to each other. The system may include a pushermember configured to advance the at least one tissue growth memberthrough the catheter. Various other embodiments may provide anchors ofvarious configuration, use of different deployment mechanisms, andtissue growth members or occluders of various configurations.

In accordance with another embodiment of the present invention, a methodfor modifying a left atrial appendage is provided. The method includespositioning a catheter adjacent the left atrial appendage. A tether isanchored within the left atrial appendage and at least one tissue growthmember is slid over the tether. The at least one tissue growth member isdeployed within the left atrial appendage and maintained therein with alocking element.

The method may further include, as part of anchoring the tether,positioning the catheter having an anchoring member in a constrainedconfiguration within the catheter relative to the left atrial appendage,and deploying the anchoring member in an expanded configuration toanchor the anchoring member in the left atrial appendage.

In one embodiment, the method may further include deploying the at leastone tissue growth member within a first lobe of the left atrialappendage and wherein the method further comprises deploying at leastone other tissue growth member in a second lobe of the left atrialappendage.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The foregoing and other advantages of various embodiments of theinvention will become apparent upon reading the following detaileddescription and upon reference to the drawings in which:

FIG. 1 is an exploded view of various components of a medical devicesystem, according to an embodiment of the present invention;

FIG. 1A is another embodiment of various components of a medical devicesystem, according to the present invention;

FIGS. 2A, 2B and 2C are cross-sectional views of a loading mechanism forloading a tissue growth member into a handle of the medical devicesystem, according to one embodiment of the present invention;

FIGS. 3A through 3D are cross-sectional views of respective stepsutilizing the medical device system for modifying a left atrialappendage utilizing the medical device system, according to anotherembodiment of the present invention;

FIGS. 4A through 4C are cross-sectional views of respective stepsutilizing the medical device system for modifying a left atrialappendage having a plurality of appendage lobes, according to anotherembodiment of the present invention;

FIG. 5 is a perspective view of an anchoring member at a distal end of atether, according to one embodiment of the present invention;

FIG. 6 is a perspective view of another embodiment of the anchoringmember deployed from a distal end of a catheter, according to thepresent invention;

FIGS. 7A through 7E are various views of components that may be used inone or more embodiments of the present invention;

FIGS. 8 and 9 are perspective views of respective distal and proximalsides of an occluder, including a tissue growth member and a frame, thatmay be employed with the medical device system of FIGS. 1 and 1A,according to an embodiment of the present invention;

FIGS. 10 and 11 is a perspective view and a simplified side view of theframe of FIGS. 7 and 8, according to another embodiment of the presentinvention;

FIGS. 12A and 12B are perspective views of a clip in an open positionand a closed position, respectively, formed in the frame depicted inFIGS. 10 and 11, according to another embodiment of the presentinvention;

FIGS. 13 and 14 are simplified perspective views of a hub in an open andclosed position, respectively, taken along a center line of the framedepicted in FIG. 10, depicting a portion of a medical device system,according to another embodiment of the present invention;

FIGS. 15A and 15B are side views of components that may be used in aframe for an occluder in accordance with various embodiments of thepresent invention;

FIG. 16 is a simplified perspective view of the frame, depicting aportion of a medical device system taken along a center line, accordingto another embodiment of the present invention;

FIG. 17 is a perspective view of a portion of the frame of FIG. 16,according to the present invention;

FIG. 18 is a perspective view of the proximal side of an occluder inaccordance with another embodiment of the present invention; and

FIG. 19 is a partial cross-sectional side view of the occluder shown inFIG. 18.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a medical device system 10 is shown that may beused to occlude or modify an opening or cavity such as, for example, aleft atrial appendage (LAA). In one embodiment, the medical devicesystem 10 may include a handle 12 with an actuator 14 and fluid port 16.The fluid port 16 may be used to flush out the catheter when in use aswill be appreciated by those of ordinary skill in the art. In addition,the system 10 includes a catheter 18 with a catheter lumen 20 extendinglongitudinally therethrough and attached to a distal end of the handle12. The catheter lumen 20 may coincide and communicate with a handlelumen 22 as well as communicate with the fluid port 16. The actuator 14may be configured to actuate or move the catheter 18 proximally anddistally, relative to an associated tether 26, to deploy and capture,respectively, an anchoring member 24 disposed at a distal end of thetether 26. The tether 26 may be configured to extend through and bepositioned within the catheter lumen 20. The tether 26 may also extendthrough the handle lumen 22 and may extend out of a proximal end of thehandle 12.

The medical device system 10 may also include a capturing member 28, apusher member 30 and a loading member 32 (which, in one example, asshown, may be configured as a funnel structure or device) may be forloading a tissue growth member 40 into the handle 12. As will bediscussed in further detail below, the tissue growth member 40 may bedisplaced through the handle 12 and over the tether 26 to a distalportion 34 of the catheter 18 for deployment during a desired procedureto modify an atrial appendage. As depicted in FIG. 1, the tissue growthmember 40 may exhibit various sizes and shapes. For example, the tissuegrowth member 40 may exhibit a shape similar to a cup, a disk, acylinder, a coil configuration, or any other suitable shape orconfiguration, such as a spherical or semispherical geometry or thelike. Such tissue growth members may also include a support structure 42extending internally or externally (or both) of the tissue growth member40. The tissue growth member 40 may be configured to be constrained andconfined within the narrow configuration of a catheter 18 and, whenreleased from the catheter, self expand to a larger configuration. Thesupport structure 42 may be configured to assist the tissue growthmember 40 to expand to its intended larger configuration as well asconfigured to assist the tissue growth member to be predictably capturedwithin the capturing member 28 and pushed distally through the handle 12and catheter 18. Such support structure 42 may be formed, for example,from a shape-memory alloy, such as a nickel-titanium alloy (alsoreferred to as Nitinol), from a polymeric material or any other suitableflexible material known in the art.

According to one aspect of the present invention, the tissue growthmember 40 may be a self expanding porous member, such as a polymer basedfoam or a polyurethane foam. Other materials with desired porosity mayalso be used, such as, for example, felt, fabric, a polyester fiber suchas polyethylene terephthalate (PET, also known commercially as Dacron®),Nitinol braded wire, or Nitinol felt. In the case of foam, such foam maybe a reticulated foam, typically undergoing a chemical or heatingprocess to open the pours within the foam as known in the art. The foammay also be a non-reticulated foam. The foam may also include gradeddensity and graded porosity, as desired, and manipulated to expand in adesired geometry when the support structure 42 is moved to the expandedconfiguration. The tissue growth member 40 is configured to inducetissue in-growth therethrough to, thereby, close the LAA opening.Further, the tether 26 may be formed from a metal or polymer basedmaterial or any other material suitable for maintaining access to theLAA with the anchor and to facilitate interconnection for one or moretissue growth members.

FIG. 1A is another embodiment of a medical device system 310 with anadditional component as compared to the embodiment shown in FIG. 1. Thesystem 310 includes an anchor catheter 319 having an anchor catheterhandle 313 with an actuator 315 and fluid port 317. The anchor catheter319 also includes an anchor 324 and tether 326 combination, similar tothat previously described, disposed within the anchor catheter 319. Assuch, the medical device system 310 includes a primary catheter 318 witha handle 312 and the anchor catheter 319 having the anchor catheterhandle 313. Although only one anchor catheter 319 is depicted, there maybe one or more anchor catheters in the system 330, depending on thenumber of tethers needed to be anchored within a particular atrialappendage. Further, the medical device system 310 of this embodimentalso may include a elements shown in FIG. 1 such as a capturing member28, loading member 32 and pusher member 30 to facilitate sliding thetissue growth member 40 in the handle 312 and through the primarycatheter 318 of this embodiment.

Referring still to FIG. 1A, the anchor catheter 319 includes an anchor324 positioned at a distal portion 334 of the anchor catheter 319 and atether 326 coupled to, and extending from, the anchor 324. As in theprevious embodiment, the tether 326 may extend through the anchorcatheter 319 and the anchor catheter handle 313. Such anchor catheter319 is sized and configured to be advanced through the handle 312 andthe primary catheter 318 (or rather through associated lumens of thehandle 312 and the primary catheter 318) for deploying the anchor 324within the LAA Likewise, the primary catheter 318 is sized andconfigured to receive the anchor catheter 319 through the handle 312 tobe advanced distally through the primary catheter 318. With thisarrangement, the primary catheter 318 may first be employed by advancingthe primary catheter 318 through the right atrium, through the atrialseptum wall via a septal puncture to enter the left atrium and navigatedadjacent the LAA, utilizing standard catheterization techniques, asknown to one of ordinary skill in the art. The anchor catheter 319 maythen be advanced in the primary catheter 318 and, further, advancedbeyond the primary catheter 318 and within the LAA. The anchor 324 maythen be deployed via the actuator 315 and anchored within the LAA. Theanchor catheter 319 may then be withdrawn from the LAA and from theprimary catheter 318, leaving the tether 326 attached to the anchor 324and extending through the primary catheter 318 while maintaining theprimary catheter adjacent the LAA. The tissue growth member 40 (FIG. 1)may then be positioned over the tether 326 and advanced in the handle312, similar to, for example, the embodiment disclosed in more detailbelow with respect to FIGS. 2A-2C.

FIGS. 2A through 2C illustrate one method for loading the tissue growthmember 40 into the handle 12 utilizing the capturing member 28, theloading member 32 and pusher member 30. For example, an opening 44defined in the tissue growth member 40 may be configured such that thetether 26 passes therethrough. In one embodiment, the opening 44 may bedefined centrally within the tissue growth member 40. The tether 26 mayalso be positioned through respective central bores 52, 54, 56 definedin each of the loading member 32, capturing member 28 and pusher member30. As depicted in FIG. 2A, the pusher member 30 may be displaceddistally through the capturing member 28 and loading member 32 and theloading member 32 may be attached to the distal end of the capturingmember 28. The pusher member 30 may include a grasping portion 58configured to grasp the tissue growth member 40. In one embodiment, thegrasping portion 58 grabs or attaches to a portion of exposed supportstructure 42 (see FIG. 1) that, for example, extends through the tissuegrowth member 40 at a location adjacent the opening 44 of the tissuegrowth member 40. With this arrangement, the pusher member 30 may bemoved distally, as indicated by arrow 55, to grab the tissue growthmember 40.

As shown in FIG. 2B, the pusher member 30 may then be displacedproximally, as indicated by arrow 57, to pull the tissue growth member40 against a surface 60 of the loading member 32 to assist the tissuegrowth member 40 to collapse or be compacted in a constricted andconfined configuration and into the capturing member 28. As shown inFIG. 2C, once the tissue growth member 40 is constricted or containedwithin the capturing member 28, the loading member 32 may be removedfrom the capturing member 28, such as indicated by arrows 59. The tissuegrowth member 40 may then be moved distally, as indicated by arrow 61,into the handle 12 (or, more specifically, the handle lumen 22) via thepusher member 30 which may continue to push the tissue growth member 40distally to a distal portion of the catheter (not shown). It is alsocontemplated that once the tissue growth member 40 is contained withinthe capturing member 28, the tissue growth member 40 may be moved to thedistal portion of the catheter by other means. For example, the tissuegrowth member 40 may be displaced hydraulically such as by pushingsaline through a fluid port to displace the tissue growth memberdistally. Further, it is contemplated that in another embodiment, thetissue growth member 40 may be loaded directly into the handle 12. Inanother embodiment, the tissue growth member 40 may be loaded orpre-loaded into a separate catheter and advanced distally over thetether 26, through the handle 12 and catheter 18, similar to thatdisclosed with respect to the anchor catheter 319 (see FIG. 1A).

Referring now to FIGS. 3A through 3D, use of a medical device system 10for modifying a left atrial appendage 15 is shown according to anembodiment of the present invention. As shown in FIG. 3A, the catheter18 of the medical device system 10 is advanced to the left atrialappendage 15 of the heart. Such may be accomplished, for example, byadvancing the catheter 18 through the septum wall of the heart via atrans-septal puncture. Imaging techniques, as known in the art, may beutilized for preferred positioning of the catheter 18 by advancing, forexample, contrast through the catheter and into the left atrialappendage 15. Once a desired position of the catheter 18 is established,the catheter 18 may be moved proximally, via the actuator 14 (FIG. 1),to deploy an anchoring member 24 from a distal portion 34 of thecatheter 18, as depicted in FIG. 3B. The anchoring member 24 is sizedand configured to self expand and lodge within the left atrial appendage15 such as by pressing and engaging against and with the walls of theleft atrial appendage 15. The anchoring member 24 is configured toreadily engage with the trabeculated tissue deep within the LAA. Thephysician or operator may pull on the tether 26, which is attached tothe anchoring member 24, to ensure that the anchoring member 24 issufficiently lodged within the left atrial appendage. If the anchoringmember 24 becomes dislodged, the anchoring member 24 may be readilyre-sheathed into the catheter 18 and another attempt may be made toposition and lodge the anchoring member 24 within the left atrialappendage 15. It is noted that the tether 26 extends from a proximal endof the anchoring member 24 and through the catheter 18. Thus, theanchoring member 24 and tether 26 combination allow the physician tomaintain catheter access to the left atrial appendage.

As depicted in FIG. 3C, a tissue growth member 40 is slid over thetether 26 through the catheter 18 and deployed in a desired positionwithin the left atrial appendage 15. As previously set forth, the tissuegrowth member 40 may be loaded over the tether 26, as shown in FIGS. 2Athrough 2C, utilizing, for example, the catheter systems depicted ineither FIG. 1 or 1A, or any other suitable method for delivering thetissue growth member 40, such as previously set forth. At this juncture,the physician may continue and utilize imaging techniques to determineif the tissue growth member 40 has sufficiently provided a surface thatwill substantially prevent thrombus from migrating from the left atrialappendage 15. If needed, depending on the wide breadth of variations ofleft atrial appendages, the physician may release one or more additionaltissue growth members 40, as depicted in FIG. 3D. Once the physician issatisfied with the procedure, a locking element 44 may be slid over thetether 26 adjacent the proximal most tissue growth member 40, afterwhich the tether 26 may be cut or otherwise terminated proximally ofsuch locking element 44. The locking element 44 may be a clamp slid upthe tether or a knot formed in the tether or any other suitable fixtureconfigured to ensure the tissue growth element 40 does not migrate fromits deployed position.

It should be noted that the medical device system of the presentinvention may include differently sized or shaped tissue growth members40 so that a physician can utilize the size and shape necessary and bestsuited to create a surface that will substantially prevent thrombus frommigrating from the left atrial appendage 15. In this manner, thephysician can obtain imaging information while conducting the procedureand determine if proper occlusion of the LAA has been obtained and, ifnot, continue to determine and selectively choose appropriately sizedadditional tissue growth members to slide into the left atrial appendageto, thereby, occlude virtually any size or other variation that may beencountered when conducting such a procedure. Furthermore, it is notedthat once the anchor 24 is lodged within the LAA for sliding one or moreof the tissue growth members 40 over the tether 26 and into the LAA 15,any potential issues of device orientation are substantially eliminatedas the tether provides a guide into the LAA 15 for placement of thetissue growth members 40.

Referring now to FIGS. 4A through 4C, another method for employing themedical device system 10 of the present invention is provided whereinthere are multiple lobes in the left atrial appendage 15. As depicted inFIG. 4A, a first tissue growth member 40 a is positioned in a first lobe17 of the left atrial appendage 15 by being slid over a tether 26 thetether 26 being held in place with the anchoring member 24 in the firstlobe 17 (such as described with respect to FIGS. 3A-3C above), and thefirst tissue growth member 40 a being prevented from migrating via thelocking element 44 locked on the tether 26 at the proximal side of thefirst tissue growth member 40 a. Another catheter 18 may then beadvanced to deploy the anchoring member 24 in a second lobe 19 in theleft atrial appendage 15 to anchor therein. As depicted in FIG. 4B, asecond tissue growth member 40 b may then be selectively chosen anddeployed in the second lobe 19 with the tether 26 maintaining access topreferred positioning within the left atrial appendage 15 via itsattachment to the anchor member 24 that has been deployed within thesecond lobe 19. As previously set forth, positioning the tissue growthmember 40 in the LAA 15, in each instance, may include the step ofloading the tissue growth member 40 over the tether 26 after the step oflodging the anchoring member 24 in the LAA 15 with the tether 26extending therefrom. In some embodiments, deployment of individualtissue growth members 40 a and 40 b may be sufficient for occlusion ormodification of the LAA 15. However, in other situations, deployment ofadditional tissue growth members may be desired or even required.

For example, as depicted in FIG. 4C, a third tissue growth member 40 cmay be selectively chosen and deployed so as to be sized and configuredto best fit within the remaining space and effectively provide a surfacethat will substantially prevent thrombus from migrating from the leftatrial appendage. Although the tissue growth members, due to the selfexpanding characteristics thereof, effectively lodge themselves withinthe left atrial appendage 15, to ensure such tissue growth members donot migrate from the left atrial appendage, the locking element 44 canbe slid over the tether 26 and clamped to the tether 26 adjacent to theproximal side of the third tissue growth member 40 c. In this manner, aleft atrial appendage 15 with multiple lobes (e.g., 17 and 19) may beoccluded to substantially prevent emboli from migrating from the leftatrial appendage 15 and, over time, the tissue growth members willinduce tissue in-growth therein to permanently create a tissue sealwithin the left atrial appendage 15.

As will be readily understood by one of ordinary skill in the art,instead of the catheter 18 employed in the embodiments disclosed withrespect to FIGS. 3A through 3D and FIGS. 4A through 4C, the anchorcatheter 319 may be employed with the primary catheter 318 as set forthand described with respect to FIG. 1A.

FIG. 5 depicts an anchoring member 24 interconnected to a distal end ofthe tether 26 according to one embodiment. Such an anchoring member 24is sized and configured to be collapsed in a constrained configurationat the distal portion of the catheter (see FIG. 1). As previously setforth, once such anchoring member 24 is deployed from the catheter, theanchoring member 24 may self expand to an expanded or deployedconfiguration, as shown. The anchoring member 24 may include multiplelegs 62 extending from a center portion 64, the center portion beinginterconnected to the tether 26. In the embodiment depicted in FIG. 5,there are four legs 62 extending from the center portion 64, however, inother embodiments there may be any suitable number of legs. Each leg 62may extend radially outward and include a looped portion 66 at theradial outermost end thereof. Such looped portion 66 extends distallyand then returns both radially inwardly and proximally such that adistal leg end 68 extends beyond a more proximal portion of the leg soas to act as an engagement nub to engage with the trabeculated tissuewithin the LAA. In this manner, the legs are sized and configured toextend within the left atrial appendage and anchor within such tissue.The looped portion 66 and the outward extending legs 62 may provide aspring effect to allow the physician to pull on the tether 26 withoutdamaging the tissue when determining if the anchoring member 24 issufficiently lodged within the left atrial appendage.

It is noted that a variety of other configurations may be employed forthe anchoring member 24. For example, a variety of anchoring structuresare disclosed in U.S. patent application Ser. No. 12/253,831 entitledMEDICAL DEVICE FOR MODIFICATION OF LEFT ATRIAL APPENDAGE AND RELATEDSYSTEMS AND METHODS, filed on Oct. 17, 2008, the disclosure of which isincorporated by reference herein in its entirety. Such anchoring systemsor structures may be incorporated into embodiments of the presentinvention in conjunction with an associated tether and tissue growthmember.

FIG. 6 depicts another embodiment of an anchoring member 25 which may beused in connection with the medical devices of the present invention. Inthis embodiment, the anchoring member 25 may include multiple j-shapedportions 72 extending radially outward to self expand from the distalportion of the catheter 18. Each j-shaped portion 72 includes a curvedextension 74 and a distal coiled end 76. The periphery of each coiledend 76 may include one or more tapered nubs 78. In this manner, thecoiled ends 76 of the j-shaped configuration can self expand and nestwithin the left atrial appendage and substantially anchor therein.Further, the spring-like quality of the curved extensions 74 allows forsubstantial pull on the tether to determine proper anchoring whilesubstantially limiting any damage to the tissue within the left atrialappendage. It should be noted that it is not required that there bythree j-shaped portions as is shown in the drawings. Rather, there maybe more or additional j-shaped portions than shown as may be desired.

Referring now to FIGS. 7A-7E, another embodiment of an anchor is shownthat may be used in accordance with one or more embodiments of thepresent invention. FIG. 7A shows a perspective view of the anchor 80,FIG. 7B shows a side view of the anchor 80, FIG. 7C shows a side view ofthe anchor 80 rotated approximately 90 degrees relative to that shown inFIG. 7B, and FIGS. 7D and 7E show side views of individual componentsused in forming the anchor 80. The anchor 80 may include multiple framemembers 81A and 81B assembled together. While the frame members 81A and81B may be substantially similar to one another, they are notnecessarily identical to each other.

For example each frame member 81A and 81B may include one or more anchorlegs 82 (in the present depicted embodiment, each frame member includestwo anchor legs) with various features. The anchor legs 82 may includean arcuate distal end 83 having increased mass compared to the rest ofthe leg 82, the arcuate distal end 83 curving radially inwardly. Sucharcuate distal ends act as atraumatic tips to help prevent potentialpuncture of the walls of the LAA when deploying the anchor 80. Theinward curvature of the anchor legs distal ends are configured so thatif the ends 83 are pushed against tissue within the LAA, the ends of theanchor legs 83 will roll radially inward. The anchor legs 82 may alsoinclude tissue engaging features 84 that are configured to press againstand engage the trabeculated tissue wall of the LAA. The engagingfeatures 84 may include, for example, proximally extending nubs, whichmay also be tapered. The engaging features 84 (as well as various tissueengaging features of other anchors and structures described herein) areconfigured to be atraumatic. For example, the engaging features 84 mayengage with the tissue of an LAA by nestling amongst the trabeculationsalong the tissue wall.

The anchor legs 82 may further include a flare 85 or projection thatextends or deviates radially outwardly relative to the remaining path ofthe anchor legs 82. The flare 85 assists in loading the anchor 80 into acatheter or other delivery mechanism such that when the flare engagesthe periphery of a catheter lumen, it causes the anchor legs 82 todeflect radially inwardly a sufficient distance to avoid theinterference of the engaging features 84 with the inner wall of thecatheter's lumen. It is also noted that the anchor legs 82 may exhibitdifferent lengths than one another to further help facilitate placementof the anchor 80 within a catheter or other delivery mechanism. Thus, inone embodiment, each anchor leg 82 of a give anchor 80 may exhibit adifferent length than every other anchor leg.

The frame members 81A and 81B also include hub members 86A and 86B,respectively, that are cooperatively configured to effect mating orassembly of the frame members 81A and 81B to form the anchor 80. Forexample, referring specifically to FIGS. 7D and 7E, the hub 86A of oneframe member 81A may include a slot 87 which may be accessed bydisplacing the free ends of two adjacent leg members 88A and 88B. Theslot 87 may be sized and configured to accept, and mate with, a bodyportion 89 of hub member 86B from the other frame member 81B. The bodyportion 89 may have engagements surfaces 90A and 90B and be sized to fitsnugly within the slot 87 of hub 86A. Other slots 91 and 92 within thehub members 86A and 86B may be used in facilitating assembly of theanchor members 81A and 81B.

The anchor members 81A and 81B may also include a plurality of throughholes 93A, 93B and 93C and/or slots 94 or notches. These through holes93A through 93C may be used for coupling of the tether 26 to theassembled anchor 80. For example, as shown in FIG. 7B, the tether 26 maypass through the various through holes 93A-93C, while also wrappingaround the assembled hub members 86A and 86B to couple the tether 26with the anchor 80 and to help maintain assembly to the frame members81A and 81B. The tether may have a clip, a knot or otherwise be staked,as shown at 95, to keep the tether 26 from becoming unattached from theanchor 80.

In one embodiment, each frame member 81A and 81B may be formed as anintegral, unitary and seamless component. For example, the frame members81A and 81B may be formed by laser cutting from a sheet of material suchas a nickel-titanium alloy. Thus, the anchor legs 82 of a given framemember 81A or 81B would lie in a common plane.

It is noted that the anchor 80, as well as other anchors describedherein, are configured to be deployed deep within an atrial appendage.The ability to vary the relative position of an anchor with anassociated tissue growth member (e.g., by varying the position of thetwo components along an associated tether) provides substantialflexibility in modifying an atrial appendage, particularly in light ofthe extreme variability from one atrial appendage to another.

With respect to FIGS. 8 and 9, there is disclosed an embodiment of anoccluder member 350, depicting perspective views of a distal side and aproximal side, respectively, of the occluder member 350. The occludermember 350 may be used in place of (or in some instances, in additionto) the tissue growth members 40 and associated support structure 42described hereinabove.

The presently considered embodiment of the occluder member 350 may beemployed with the medical device system depicted in FIG. 1 or FIG. 1A.The occluder member 350 includes a tissue growth member 352 and a frame354. As with previously described embodiments, the tissue growth member352 may include a porous member configured to promote tissue in-growththerein. The tissue growth member 352 may be a polymeric material, suchas foam or other materials such as discussed above. In the embodimentshown in FIGS. 8 and 9, the tissue growth member 352 may exhibit acup-like shape having an outer (or convex) surface 356 and an inner (orconcave) surface 358, the outer surface 356 including a distal surfaceportion 360 and a proximal surface portion 362. The distal surfaceportion 360 of the tissue growth member 352 is sized and configured tobe in direct contact with tissue within the LAA (such as shown withrespect to tissue growth members 40 a-40 c in FIG. 4C).

The frame 354 or support structure of the occluder member 350 isconfigured to assist in expanding the tissue growth member 352 and toassist in collapsing the tissue growth member 352 for delivery throughan associated catheter or other medical device. Such frame 354 mayinclude an expander portion 366, a collapser portion 368 and a hubportion 370. The expander portion 366 may extend from the hub portion370 with multiple expanding legs 372. In one embodiment, the legs 372may extend along the inner surface 358 of the tissue growth member 352.The collapser portion 368 also may extend from the hub portion 370 withmultiple collapsing legs 374. In one embodiment, the collapsing legs 374may extend along the proximal surface portion 362 of the tissue growthmember 352. With this arrangement, the collapser portion 368 of theframe 354 assists in collapsing the tissue growth member 352 (such asduring a loading procedure) to a size wherein the occluder member 350fits within the lumen of a catheter and may be displaced therethroughwithout damaging the tissue growth member 352. Further, when deployingthe collapsed tissue growth member 352 from a catheter, the expanderportion 366 of the frame 354 is configured to self expand to assist inopening the tissue growth member 352 so that much (if not all) of thedistal surface portion 360 of the tissue growth member 352 is in directcontact with the tissue of the LAA.

Referring now to FIGS. 10 and 11, FIG. 10 shows a perspective view andFIG. 11 shows a side view of the frame 354 previously described withrespect to FIGS. 8 and 9. FIGS. 10 and 11 do not depict the tissuegrowth member 352 for purposes of clarity. Additionally, FIG. 10 isshown in a simplified form (i.e., some frame components are not shown)for purposes of clarity.

The frame 354 may include multiple discrete frame segments 364 that maybe assembled with the hub portion 370 to collectively provide the frame354. Each frame segment 364 includes a hub extension 376 with anexpanding leg 372 and a collapsing leg 374 extending from a proximal end376 of the hub extension 376.

Further, each frame segment 364 is configured to be substantially flat.Otherwise said, the hub extension 376, expanding leg 372 and collapsingleg 374 of a given frame segment 364 are substantially coplanar withrespect to each other. In one embodiment, the frame segments 364 mayeach be laser cut or otherwise formed from a flat sheet of Nitinol,thereby, providing a substantially flat configuration to each of theframe segments 364. In this manner, the frame 354 (when assembled fromthe plurality of frame segments 364) may be configured to collapsewithin a catheter as well as self expand when deployed from a catheterwith the frame segments 364 being deflected and displaced in theprocess.

Each frame segment 364 may be positioned radially and substantiallysymmetrical with respect to each other about a longitudinal axis 375that extends through the hub portion 370. The frame segments 364 may becoupled with one or more rings 378 having notches on a radial innersurface, a radial outer surface or both to correspond with notchesformed within the hub extension 376 of the frame segment. Due to eachframe segment 364 being discrete with respect to the other framesegments 364, the expanding leg 372 and collapsing leg 374 may collapseor expand substantially independent from the other expanding andcollapsing legs of the other frame segments 364. With this arrangement,when the tissue growth member 352 is deployed from a catheter, each ofthe frame segments 364 self expand, independent of each other, tofacilitate the tissue growth member 352 to be in direct contact with thetissue of the LAA in a non-rigid and conformable manner. Further, theframe segments 364 each independently self expand so as to adapt to thevarying anatomy that is encountered within the LAA.

Each of the collapsing legs 374 and the expanding legs 372 may includeone or more clips 380 formed therewith. FIGS. 12A and 12B areperspective enlarged views of clips 380 in an open and closed position,respectively, in accordance with an embodiment of the present invention.Such clips 380 may be formed in the proximal and/or distal portions ofthe legs for attaching the tissue growth member thereto (see FIGS. 8 and9). The clips 380 may include a leg base portion 382, a cantileveredextension 384 with a free-end 386, and a pawl 388 that is configured toreceive the free-end 386 of the cantilevered extension 384. Also, theclips 380 may include nubs 390 extending from the leg base portion 382to provide traction or additional engagement with the tissue growthmember 352. With the clips 380 formed in the collapsing and expandinglegs of the frame, portions of the tissue growth member 352 are tuckedbetween the cantilevered extension 384 and the leg base portion 382 andclipped to the legs by simply closing or pressing the free-end 386against the pawl 388 until the free-end snaps under the pawl and islocked in position. As shown in FIGS. 10 and 11, the clips 382 may beintegrally formed into the frame segments, such as by laser cutting. Inother embodiments, other means of fastening the tissue growth member 352to the frame 354 may be used (in lieu of, or in addition to the clips380) including, for example, adhesives, sutures, or other mechanicalstructures or devices.

Referring now to FIGS. 13 and 14, a simplified side view of portions ofa medical device system 400 in an open position (also referred to as anexpanded or deployed position) and a closed position (also referred toas a contracted position), according to one embodiment, is depicted. Themedical device system 400 may include the occluder member 350, a tetherfilament 402 and a pusher member 404. It is noted that, for purposes ofclarity, a tissue growth member is not shown in FIGS. 13 and 14,although one is contemplated and those of ordinary skill in the art willrecognize its use an implementation in the following description.Additional reference is made during the following description to FIGS.15A and 15B which show side views of frame segments 364A and 364B. It isnoted that the frame 354 of the occluder member 350 may be formed of aplurality of frame segments 364A and 364B. In one embodiment, the frameof the occluder member 350 may include four of each type of framesegments 364A and 364B which alternate in their positions (i.e., eachframe segment 364A is adjacent to two frame segments 364B and viceversa). As set forth above, the frame segments 364A and 364B may includeexpanding legs 374, collapsing legs 372 and hub extensions 376 that haveinner and outer notches 379 for engaging ring members during assembly ofthe frame. As previously noted, such frame segments 364A and 364B may beformed, for example by laser cutting from a flat sheet of desiredmaterial such as a nickel-titanium alloy (e.g., Nitinol). Such aconfiguration provides for the expanding leg 374, collapsing leg 372 andhub extension 376 to be coplanar.

Additional detail regarding the function and structure of a hub portion370 of the occluder member 350, as facilitated with the tether filament402 and the pusher member 404, is now set forth in accordance with oneembodiment of the invention. The hub portion 370 may define a hole 406extending centrally therethrough and may further include a threadedportion 408 that at least partially defines the hole 406. As previouslyset forth, the hub portion 370 is defined via the assembled multiple hubextensions 376 radially oriented and positioned with the one or morerings 378. The hub portion of the frame 354 enables the occluder member350 to slide over the tether filament 402, such as previously depictedin the embodiments described in FIGS. 3A-3D and 4A-4C.

The pusher member 404 includes a distal end 410 and a proximal end (notshown) with a lumen 412 extending longitudinally through at least aportion of the pusher member 404. The pusher member 404 includes acoupling member 414 at or proximate the distal end 410 of the pushermember 404 and a cutter 416 disposed within the lumen 412, a distal endof the cutter 416 being proximal or adjacent to an outlet 422 defined ina wall of the pusher member 404. The coupling member 414 may include athreaded portion 418 and a non-threaded distal extension 420, theextension 420 extending distal of the threaded portion 418.

As depicted in FIG. 13, when the threaded portion 418 is fully engagedwithin the hole 406 defined in the hub portion 370, the non-threadeddistal extension 420 engages the hub extensions 376 and places a gripperportion 424 of the hub portion 370 in an open position. In this manner,the occluder member 350 may slide or move over the tether filament 402,through a catheter while in a collapsed position as well as oncedeployed from the catheter, with the tether filament 402 extendingthrough at least the coupling portion 414 or a distal portion of thepusher member 404 and exiting from the pusher member 404 through theoutlet 422 defined in the wall of the pusher member 404.

With respect to FIG. 14, once the occluder member 350 is positioned asdesired such that the tissue growth member (not shown) is in directcontact with tissue in the LAA, the pusher member 404 may be un-threadedor removed from the occluder member 350, thereby causing the gripperportion 424 of the hub portion 370 to engage or grip the tether filament402. That is, as the pusher member 404 is un-threaded, the distalextension 420 is moved proximally which causes the gripper portion 424to move to the radially inward position (i.e., the radially closedposition) to grip onto the tether filament 402 that is anchored distallyand deep within a lobe of the LAA. In one embodiment, the gripperportion 424 may include bands 426 disposed around the gripper portion424 to bias the gripper portion in the closed state and assist in moreeffectively gripping the tether filament 402. In other embodiments, thehub extensions may be configured to be biased towards the closedposition even without the aid of other biasing elements. Thisconfiguration enables the hubs to work as a locking element to maintainthe occluder member 350 in a desired position relative to the tether(and, thus, relative to an associated anchor).

The pusher member 404 can then be fully removed from the hub portion 370of the occluder member 350 and, if the physician is satisfied with theposition of the occluder member, the cutter element 416 can be moveddistally to slice the tether filament 402. Alternatively, depending onthe anatomy of the LAA, another occluder member may be loaded in acatheter and slid over the tether filament 402 to position within theLAA.

With reference to FIGS. 16 and 17, another embodiment of a portion ofthe medical device system 400 is depicted. This embodiment is similar tothe embodiment described with respect to FIGS. 14 and 15, except in thisembodiment, the hub extensions 376 may include a guide portion 430 thatmay be associated with the gripper portion 424. Further, at the distalend of the guide portion 430, there is a pawl 432 to latch a tetherguide coil 434. The tether guide coil 434 extends distally and thetether filament 402 extends axially through the tether guide coil 434.The tether guide coil 434 extends a length sufficient to substantiallyprevent the tissue growth member (not shown) from contacting the tetherfilament 402 while the occluder 350 is in a collapsed position and beingpushed distally within a catheter.

It is also contemplated that the pusher member 404 may include a coil(not shown) that is positioned proximal to the coupling member 414 andover the pusher member 404 such that the coil and the lumen 412 of thepusher member 404 have a common axis. Further, it is also contemplatedthat the occluder 350, the pusher member 404 and the tether filament 402may include radiopaque characteristics or markers so that the relevantportions of the medical device system 400 can be viewed with imagingtechniques known in the art.

Referring now to FIGS. 18 and 19, an occluder 350 is shown in accordancewith another embodiment of the present invention. FIG. 18 shows a frontperspective view while FIG. 19 shows a side, partial cross-sectionalview of the occluder 350. The occluder 350 is similar to the embodimentsshow and described with respect to FIGS. 7 and 8, but also includes anadditional material layer 390 associated with the tissue growth member352. FIG. 19 shows the additional material layer 390 in an “exploded”state for purposes of illustration. However, the additional materiallayer 390 is, in actuality, contiguous with the underlying foam or othermaterial forming the tissue growth member 352, the additional materiallayer 390 being attached thereto by, for example, an adhesive. Theadditional material layer 390 may include a polytetrafluoroethylene(PTFE) or expanded PTFE (ePTFE). Such a surface provides a smoothsurface on the proximal side of the tissue growth member to tailor thetissue growth pattern once the occluder is deployed within an atrialappendage. It is noted the additional material layer 390 may beconfigured to allow a portion of the frame to be exposed on the proximalside (e.g., the hub portion) such as shown in FIG. 18, or it may beconfigured to cover substantially all of the frame along the proximalside such as is shown in FIG. 19.

While the invention may be susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, it should be understood that the invention is not intended tobe limited to the particular forms disclosed. Rather, the inventionincludes all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the followingappended claims.

What is claimed is:
 1. A method for modifying a left atrial appendage,comprising: positioning a catheter adjacent the left atrial appendage;pushing a medical device having tines through a lumen of the catheter;anchoring the medical device within the left atrial appendage; deployinga tissue growth member of the medical device from the catheter, themedical device rotatably coupled to a threaded pusher member; andmaintaining the at least one tissue growth member in the left atrialappendage with a locking element, the locking element including multiplefingers that collapse directly dependent upon proximally moving thethreaded pusher member relative to the tissue growth member.
 2. Themethod according to claim 1, wherein anchoring the medical devicefurther comprises anchoring the medical device with a tether coupledthereto.
 3. The method according to claim 1, wherein the deploying thetissue growth member comprises pushing the tissue growth member over atether coupled to the medical device.
 4. The method according to claim3, wherein pushing the tissue growth member over the tether furthercomprises positioning the catheter within the left atrial appendage anddeploying the tissue growth member from the catheter while slidablycoupled with the tether.
 5. The method according to claim 1, wherein thedeploying the tissue growth member further comprises deploying thetissue growth member having self-expanding frame members coupled to apolymeric element.
 6. The method according to claim 2, furthercomprising disengaging the threaded pusher member from the medicaldevice.
 7. The method according to claim 6, wherein the disengagingcomprises cutting the tether with a cutting element.
 8. The methodaccording to claim 6, wherein the disengaging comprises collapsing themultiple fingers of the locking element over the tether by proximallymoving the threaded pusher member.
 9. The method according to claim 1,wherein the maintaining comprises disengaging the threaded pusher memberfrom the medical device.
 10. The method according to claim 1, whereinthe deploying comprises maintaining the multiple fingers of the lockingelement in a non-collapsed position with a distal portion of thethreaded pusher member engaged with a hub of the medical device.
 11. Amethod for modifying a left atrial appendage, comprising: positioning asheath adjacent the left atrial appendage; pushing a medical devicehaving tines through a lumen of the sheath; anchoring the medical deviceto the left atrial appendage with the tines; deploying a tissue growthmember of the medical device from the sheath; and disengaging a threadedpusher member from the medical device upon collapsing multiple fingersof a locking element directly dependent upon proximally displacing thethreaded pusher member relative to the tissue growth member.
 12. Themethod according to claim 11, wherein the disengaging comprises cuttinga tether with a cutting element.
 13. The method according to claim 12,wherein the disengaging comprises collapsing the multiple fingers of thelocking element over the tether.
 14. The method according to claim 11,wherein anchoring the medical device further comprises anchoring themedical device with a tether coupled thereto.
 15. The method accordingto claim 11, wherein the deploying comprises maintaining the multiplefingers of the locking element in a non-collapsed position with a distalportion of the threaded pusher member.
 16. The method according to claim11, wherein the deploying the tissue growth member further comprisesdeploying the tissue growth member having self-expanding frame segmentscoupled to a polymeric element.